Some great info here.
Before you start throwing money at possible solutions have a look at SharpCap Polar Alignment.
http://www.sharpcap.co.uk/sharpcap/polar-alignment
Google 'Astrotrac - SharpCap' for some user experience.
I had a very long, hard look at the Astrotrac, mainly for it's portability, but eventually decided to go more mainstream with a HEQ5 Pro with no regrets. I think the dicky polar scope turned me off although there seems to be work- arounds. The add-ons weren't cheap either.